1. Field of the Invention
The present invention pertains to a connector element for glass post-and-beam constructions, in which the posts and beams are made of glass, meaning that the glass posts and beams fulfill a load-bearing function, where the load is transmitted between the beam and the post by way of a glass element. The present invention also pertains to a glass post-and-beam construction.
2. Description of the Related Art
The obvious and most important properties of glass are its ability to transmit light and its transparency. As a result, glass has become an important construction material and design element in architecture in recent years. To an increasing extent, architects are now developing plans in which glass is also used as a construction material to form load-bearing structures. These types of transparent structures are often used to create meeting places, communications areas, and corridors for connecting two or more buildings.
In applications of this type, there is a need for a type of post-and-beam construction made entirely of glass to satisfy the architect's requirements for transparency.
Glass, when used in the construction industry, can be categorized generally on the basis of its application as either flat glass, sectional glass, or glass block. In the usual case, the glass will be of the alkali silicate type. This contains a large amount of silicate. When the glass is installed horizontally, it is usually enclosed by a frame so that it can withstand the forces exerted by wind and snow. Such glass must also support its own weight. For this purpose, panes of glass are usually supported on several edges and are thus subjected to bending loads. This has been the standard area of application for glass so far, but today the use of glass as a load-bearing element in itself is becoming increasingly fashionable. “Load-bearing glass” is understood here to be a load-bearing structure consisting entirely of glass. These glass structures include, for example, beams, posts, frames, diagonal struts, stiffeners, etc.
Glass is basically a brittle material, which also has ideal elasticity. Thus glass will fracture without any plastic deformation at all. These properties of glass must therefore be taken thoroughly into account when glass is used as a load-bearing element. For this reason, glass has been defined in various ways in the past, such definitions pertaining either to the material itself or to its state. Glass can be described as a “frozen, supercooled melt”.
Float glass, single-pane safety glass, and also partially prestressed glass can be used as the basic elements of load-bearing glass structures. These types of glass are usually made into laminated safety glass. Because these types of glass are already known in themselves, there is no need to discuss them in greater detail here.
Damage to glass, such as the fractures which are or can be caused especially by the stress imposed by different temperatures, proceeds from the edges. The processing of the edges by grinding will increase the strength of the edges, because such processing removes the macrocracks which are formed when the glass is cut.
It is ideal for the surface of the glass to be free of scratches, cracks, and notches, for when a glass pane with preliminary damage is subjected to tensile stress, for example, excessive stress peaks develop at the tips of the cracks. If the strength of the material is exceeded, it can be assumed that supercritical crack growth will occur and that, once such growth has been initiated, the pane will undergo sudden fracture.
Examples of “load-bearing glass” have been published in a research report under the title “Glasträger, Bericht Nr. 20, ETH Zürich, Institut für Hochbautechnik” [Glass Beams, Report No. 20, Zurich Institute of Technology, Department of Structural Engineering], pp. 31-32. The object described here is a glass structure built on the testing grounds of the Architecture Department of Rhine-Westphalian Institute of Technology in Aachen. Both the posts and the beams and therefore the entire load-bearing structure are made of glass. The overlapping areas of the glass posts and beams are connected by the use of holes, which pass through the glass elements and through which suitable metal screw elements are inserted. Single-pane safety glass is used. Because the beams are screwed to the posts, the glass elements (beams, posts) are connected solidly together. The dimensions of these holes must remain within narrow tolerances to ensure that a sufficiently large contact surface is present between the screw heads or nuts and the surface of the glass. For the reasons explained above, these types of holes are relatively expensive to produce.